1. Field of the Invention
The invention pertains to systems for detecting impairment of the operating ability of transportation vehicle operators, especially motor vehicle operators, and for alerting the operator when a state of impairment is detected.
2. Description of the Prior Art
It is well known that a great many serious injuries and fatalities are caused each year by motor vehicle accidents resulting from impairment of driving ability of the vehicle operator, which may arise from a number of different causes. Many such accidents are caused when operators have driven too long without sleep, and begin to fall asleep at the wheel, often without realizing their state of impairment. Even if the operator does not actually fall completely asleep, the operator in the sleepy state will have substantially impaired alertness and reflexes, and may be unable to respond in time to some hazard encountered in traffic.
Or an operator may have consumed alcoholic beverage, and may have reached a greater state of intoxication, then he or she realizes. Such partial intoxication, besides substantially dulling the reflexes, can also make the operator sleepy and generally less alert to the requirements of proper driving in traffic.
There are a variety of other physical conditions which may cause an operator to become too sleepy to safely operate the vehicle. Narcolepsy, for example may cause an operator to suddenly fall asleep, without warning. Sometimes an operator may suddenly become too sleepy, or insufficiently alert, as a result of the effects of aging.
In many instances an early sign of imminent serious operator impairment, is a change in inclination of the head, which will be different in nature from normal head inclinations that occur during driving. Fakhar et. al., "Effect of Sound and Vibration on Vigilance", Laboratoire Energie Nuisances (LEN) (France), INRETS No. 153, 1992, at 90-92.
Research has confirmed this correlation between change in head inclination and reduced attentiveness. This is attributed to physiological changes in muscle tone, resulting in a progressive change in head and neck alignment, culminating in "nodding off".
Numerous devices have heretofore been disclosed for producing an audible awakening alarm responsive to a predetermined tilt angle of the operator's head. Devices of such nature adapted to be worn on the operator's ear are described for example in U.S. Pat. Nos. 3,045,225; 4,354,179; and D294,562. Despite the several design modifications shown in said patents, the ear-mounted devices, unless custom fitted to the particular operator, are uncomfortable to wear, and are likely to fall off the operator's ear. Such devices also cannot be used with the concomitant wearing of eyeglasses.
Eyeglass-mounted tilt angle alerting devices are disclosed in U.S. Pat. Nos. 4,875,030 and 4,272,764. When built into the earpiece of the eyeglass frame, as in U.S. Pat. No. 4,875,030, the expense of the overall eyeglass plus alerting device is considerable. When clamped onto the earpiece of the eyeglass, as in U.S. Pat. No. 4,272,764, there is considerable discomfort to the wearer.
Tilt angle alerting devices have been described in association with hats or caps that would be worn by the vehicle operator. For example, U.S. Pat. No. 4,272,764 discloses an alerting device that is clamped onto the side of a baseball-type cap. Although potentially effective in such manner of use, the clamp component is pressed against the wearer's head, thereby producing discomfort with long-term use. U.S. Pat. Nos. 5,923,263 and 5,522,092 involve devices of complex construction and interactive with a hat in a specialized manner to make the hat unattractive and restricted to use only for the specialized purpose of providing an overall sleep-alerting apparatus.
It is accordingly an object of the present invention to provide a sleep alert apparatus involving a baseball-type cap and a tilt-monitoring device removably associated with the exterior of said cap.
It is another object of this invention to provide a sleep alert apparatus as in the foregoing object which is comfortable to use and does not depreciate the appearance of the cap.
It is a further object of the present invention to provide a sleep alert apparatus of the aforesaid nature which is of simple, durable construction amenable to low cost manufacture.
These objects and other objects and advantages of the invention will be apparent from the following description.